Digital Thermometer with stand alone Arduino Uno

Temperature Logger with SD card (YwRobot), RTC clock (DS1307) and LCD screen (Nokia 5110). The temperature is measured by the thermistor of 10kohm.

The measuring temperature values are saved to SD card with different file name in every start of logging. Parallel, the sensor gives live measurements, and can be monitored through software made in Processing Language.

LCD screen indicates the time, date and the live temperature value. However it has a menu which have options like adjusting the frequency of sampling (seconds, minutes or hours), starting or stopping the logging to SD card and also there is an option to adjust time and date of the RTC clock. All the moves become with two buttons.
The LCD is able to come in sleep mode after 1 minute of inaction in order to save battery energy. It is able to wake up by pressing the button for 3 seconds.
There are messages that notify the user for the status of file or the SD card and also if for any reason you have to eject the card during logging the file, the program closes the file to preventing the possible damage of file or SD card.
The project is an effort to use the stand alone microcontroller of Arduino Uno (Atmega 328) with the other electronics parts in order to be portable and independent device.

The connected pins are described in the arduino code. The connection of RTC clock are 4 and 5 Analog pins of arduino and temperature sensor (thermistor) connected to the 0 analog pin. For a stand alone Arduino Uno ,the only way you have is to follow the pins of Atmega328 microcontroller.

The external software (Processing Language) can be use, if you have connected the parts with the Arduino Uno from the USB port to PC. In my project I have not added yet any USB to Serial circuit connected with the standalone Atmega328 microcontroller. The software is able to create different excel files depending on date and time. For more details visit the blog:http://roscovnicoff.blogspot.com/2012/02/digital-thermometer-with-arduino-uno.html

Important: There are two points of attention of this project.
1. RTC Clock:
(a)In order to function properly the RTC clock you have to connect the GND of the CR2032 Cell Holder, with the GND of the main circuit (5 Volt).
(b)Also, you have to use not any crystal of 32.768 kHz, but a crystal which is used in watches (22pF)

LCD Nokia 5110: The library of the LCD Nokia 5110 is very essential if you want to use together LCD and SD card, else there is no any case to work together. You can download the library from http://code.google.com/p/pcd8544/")

For more help and share knowledge you can send email in: dmaggioris@gmail.com